Tool for turning large diameter objects on petroleum cokers

ABSTRACT

Apparatus and methods for turning large diameter circular members in limited areas. A circular member having holes capable of receiving a pin is fitted with a semi-circular collar having an inwardly facing pin and outwardly facing ratchet holes capable of receiving a hydraulic ram pin along its outer radius. A jack having a hydraulic ram end on one end and a fixed rotating point at the other is used to apply a tangential force to the circular member so as to rotate the circular member.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a tool for turning large diameter objects inlimited work areas and more particularly relates to the turning of alarge nut used on petroleum coking equipment.

2. Description of the Prior Art

Delayed coking is a well-known process. Typically, each coker comprisesa vertically-oriented cylindrical drum. The drum has a top head and abottom head covering and sealing the top and bottom, respectively, ofthe drum. The drum is a massive vessel, typically about twenty-six feetin diameter and about eighty-six feet tall. The top head and the bottomhead also are massive devices, being about six feet in diameter and eachweighing approximately two and one-half tons.

Heavy liquid hydrocarbon feed to the coker typically is preheated in aheater to a temperature in the range of about 700° to 900° F. Thefeedstream is thermally cracked in the coke drum for an extended periodof time during the coking cycle to produce gas and gas oil and otherhydrocarbon product streams of various boiling ranges and to form porouscarbonaceous petroleum coke. The gas and normally liquid product streamsare removed as vapors during the coking cycle from the top of the drum,and the coke remains in the drum at the end of the coking cycle. Thehydrocarbon feed is switched from the coke drum to a second parallelcoke drum while the first drum is taken off-line, and coke is removedfrom the first drum.

Hydrocarbon feed to each coker is typically fed to the on-line coke drumthrough an inlet port which is typically incorporated into the drumbottom head, and product vapor streams exit the vessel through processan outlet port, which is typically incorporated in the top head.

The coke is then cleaned using steam to remove any entrainedhydrocarbons and is cooled with water. To remove the coke from theoff-line drum, the top and bottom heads of the drum must be removed.After both the top and bottom heads and the chute cover are removed, thecoke in the drum is cut by a hydraulic water jets using, for example, a3000 psi water rotating water drill. First, a vertical pilot hole isdrilled through the core of the coke to provide a channel for cokedischarge through the bottom opening of the coke drum. Then, the waterdrill is directed against the upper surface of the coke at a distancefrom the central discharge core and cuts the coke into pieces, whichpieces fall out of the drum, and through the pilot hole. The water drilljet is moved in both a circular and vertical pattern until all of thecoke is cut and falls from the drum into a discharge chute and then onto coke storage.

In order to change from the coking where hydrocarbons exit the top ofthe coker drum, to the drilling mode where the drill stem is positionedover the top of the coker drum, a coker drill stem must be swung to thetop of the coker. A gearbox is used to swing the coker drill stem. Thegearbox swivel assembly has a large nut, approximately eleven inches indiameter having several holes in its outer diameter capable of receivinga pin. The maintenance and repair requirements for the gearbox swivelassembly require the removal and replacement of the nut. The nut islocated a limited area between several upright members on the assembly.

In the past, this large nut has required two people using a largespanner wrench and a mallet to apply the necessary torque. The spannerwas fit around the nut and its pin fit into one of the holes on the nut.The first person held the spanner while the second pounded the spannerwith a mallet. This method is labor intensive, time consuming anddifficult in the limited area available because the wrench must be movedto several times around the circumference of the nut to turn it. Inaddition, it required two people and its physical location made itdifficult to work on safely. There is a need for a simple and effectivemeans for one person to safely apply the torque needed to turn thislarge nut in the limited area available.

SUMMARY OF THE INVENTION

In accordance with this invention, a new apparatus for turning a largenut in a limited space is provided. This apparatus comprises:

An apparatus for applying a tangential force to a large, substantiallycircular member capable of receiving a pin at a plurality of locationson its outer diameter, comprising:

(a) a semicircular collar having an inner radius;

(b) a pin attached to the inner radius of the collar capable of matingwith said circular member for transferring the tangential force to thecircular member; and

(c) a notched outer radius for transmitting the tangential force to thesemicircular collar; whereby the tangential force necessary to turn themember can be applied in a limited area. By use of the apparatus andmethod of this invention, the large nut can be simple and effectivelyturned in the limited area available.

BRIEF DESCRIPTIONS OF DRAWINGS

FIG. 1 illustrates a schematic for a typical petroleum coking drum.

FIG. 2 illustrates in more detail the gearbox swivel assembly for thecoker drill stem.

FIG. 3 illustrates a stationary portion for one embodiment of thepresent invention.

FIG. 4 illustrates a movable semicircular collar for use with oneembodiment of the present invention.

DESCRIPTION OF PREFERRED EMBODIMENTS

The invention is illustrated with reference to the drawings wherein, forpurposes of illustration, it being understood that this invention is notlimited thereto. The drawing figures are not necessarily to scale andcertain elements are shown in generalized or somewhat schematic form inthe interest of clarity and conciseness The same number is used in eachdrawing to identify the same or similar components.

FIG. 1 illustrates a schematic for a typical petroleum coking drum.Referring now to FIG. 1, coking drum 1 is illustrated with an upper lid2, a lower lid 3, a feed inlet 4 for introduction of crude and a feedline 5. An aperture 6 with an end flange 7 is provided in the upper lid.A fluid source 8 is provided at one end of drill stem 9; a cutting tool10 is provided at a second, opposite end of the drillstem 9. Gearbox 101is positioned on drillstem 9 between cutting tool 10 and fluid source 8.Gearbox 101 is attached to gearbox swivel assembly 103 throughstructural member 102.

FIG. 2 illustrates in more detail gearbox swivel assembly 103. As wasmentioned above, structural member 102 is affixed to gearbox swivelassembly 103 on shaft 104. Shaft 104 fits slidably through top 106 ofassembly 103. Top 106 is positioned above base 108 by several uprightmembers 110 and provides lateral support for shaft 104. For clarity onlytwo upright members are shown but three or more members may be employedto support top 106 and stabilize shaft 104. Shaft 104 fits slidably intobase 108 which provides the motive force (not shown) for turning shaft104 and thereby turning drillstem 9 and gearbox 101 through structuralmember 102. Nut 112 is threaded on shaft 104. Nut 112 is large indiameter, for example, eleven inches, and has six evenly spaced holes114 around its circumference. Holes 114 are designed to be capable ofreceiving a pin from a tool for loosening or tightening of nut 112.

FIG. 3 illustrates a stationary portion for one embodiment of thepresent invention. Fixture 300 is fitted around upright 110 and held atthe appropriate vertical position by tightening bolt 302 against upright110. Hydraulic ram holder 304 is rotatably attached to fixture 300through pivot pin 306 which is threaded into fixture 300. Pin 306 is,for example, a cylinder approximately 4 inches in length and 1.25 inchesin diameter formed from any suitable material including but not limitedto a B-17 steel. Hydraulic ram holder 304, while unable to move alongits axis, is free to rotate about pivot pin 306. Hydraulic ram holder304 is capable of receiving hydraulic jack 308 which can be any one of anumber of hydraulic jacks well known in the art and including, but notlimited to, a porta-power hydraulic jack. Hydraulic pressure is suppliedvia supply line 310 so as to move hydraulic ram pin 312 along the axisof jack 308 as is well known in the art. Hydraulic ram pin 312 isconnected to ram 314 of hydraulic jack 308 and can be, for example, acylinder approximately 2.5 inches in length and 1 inch in diametersuitably connected to ram 314 through, for example, a threadedconnection. Hydraulic ram pin 312 may be fabricated out of any suitablematerial, including, for example, B7 steel.

FIG. 4 illustrates a semi-circular collar for use with one embodiment ofthe present invention. Semi-circular collar 400 is an arc whose innerradius 402 is substantially the same as the outer radius of nut 112.Collar 400 can be fabricated any suitable material, for example, halfinch flat bar steel. Semi-circular collar 404 includes a top 406, amiddle, 404, and bottom, 408. Top 406 and bottom 408 are attached tomiddle section 404 perpendicular to its face. Semi-circular collar 400may, for example, form an arc of approximately 150°. Top 406 and bottom408 include a number of ratcheted cutouts 410 suitable for allowing thetransmission of the linear motion of hydraulic ram pin 312 and ram 314to collar 400. The height of middle 404 and spacing between top 406 and408 is larger than the diameter of ram 314 so as to allow ram 314 to bepositioned between tops 406 and bottom 408, if necessary. Ratchet holes410 can be positioned, for example, 20° apart along the outer radius ofsemicircular collar 400. Pin 412 extends inwardly and is perpendicularto the face of middle 404 and is suitably attached thereto. Attachmentto middle 404 can be accomplished using any one of a number of methodswell known in the art, including a threaded connection. In addition, ifnecessary, additional structural support, not shown, can be provided tosemi-circular collar 400 in the vicinity of pin 412.

In operation, fixture 300 is mounted firmly on one of the uprights 110on swivel assembly 103. Bolt 302 fixes the vertical location of thevertical location of fixture 300. Hydraulic jack 308 is then slid intoholder 304. Semi-circular collar 400 is fitted on nut 112, and pin 412is firmly seated in one of the six holes 114. Hydraulic ram pin 312 isthen placed into a ratchet hole 410.

The operator then increases the pressure provided to hydraulic jack 308through hydraulic line 310 and ram 314 begins to move outwardly fromhydraulic jack 308. The linear motion of ram 314 and ram pin 312 appliesa tangential force to semi-circular collar 400 through ratchet hold 410.This tangential force is transmitted from semi-circular collar 400through pin 412 to hole 114 thereby causing nut 112 to rotate.

During this operation, semi-circular collar 400 will begin rotation and,thus, hydraulic jack 308 must be free to rotate as necessary to continueto apply the force to semi-circular collar 400. In order to accomplishthis, holder 304 rotates about pivot pin 306 thereby allowing thecontinued application of force to semi-circular collar 400 as it beginsto rotate.

If necessary, when ram 314 is fully extended, for example, collar 400can be repositioned using a second hole 114 on the outer radius of not112 and the procedure can be repeated as necessary until nut 112 isremoved.

This same procedure can be used to tighten nut 112 by using theappropriate positioning of fixture 300 and semi-circular collar 400.

While this invention has been described for use with a coker drum, itwill be obvious to those skilled in the art that the apparatus andmethod described herein may be applied generally, and in particular tomany other situations where large diameter circular members must beturned in limited areas.

Having thus described the invention by reference to certain of itspreferred embodiments, it is respectfully pointed out that theembodiments described are illustrative rather than limiting and thatmany variations and modifications are possible within the scope of thepresent invention. Many such variations and modifications may appearobvious and desirable to those skilled in the art based upon theforegoing description of the preferred embodiment.

Having thus described the invention, we claim:
 1. An apparatus forapplying a tangential force to a large, nut having a substantiallycircular periphery on a petroleum coking unit circular member which nutis adjacent and in close proximity to an upright member of the cokingunit of an assembly for holding the circular member and which nut iscapable of receiving a pin at a plurality of locations on its periphery,comprising:(a) a removable semicircular collar having an inner radiussubstantially the same as the periphery of the nut capable of fittingbetween said upright member and the nut; (b) a pin attached normal tothe inner radius of the collar capable of mating with the outer radiusof the nut for supporting said semicircular collar on said nut and fortransferring the tangential force to the nut; (c) a jack having a fixedand a movable end along one axis capable of producing the tangentialforce; (d) a notched outer radius on said semiconductor collar fortransmitting a tangential force to the semiconductor collar capable ofengaging the movable end of the jack for applying the tangential forceto the nut; (e) a fixture capable of receiving the fixed end of the jackremovably attached to said upright member for holding the circularmember thereby prohibiting motion along the axis of the jack during theapplication of the tangential force to the semicircular collar;wherebythe tangential force necessary to turn the nut can be applied in alimited area.
 2. The apparatus of claim 1, wherein the jack is aportable hydraulic jack.